Photographic materials



Patented Feb. 13, 1945 UNITED 1 STATES PHOTOGBAPHIC MATERIALS Edward Bowes Knott, Wealdstone, Harrow, England, assignor to Eastman Kodak C mnanr.

, Rochester, N. Y., a corporation of New Jersey No Drawing. Application January 23, 1943, Serial 1532473389. In Great Britain February 11,

4 Claims. ion. 95-1) This invention relates improvements in light-sensitive photographic materials. The invention-is particularly applicable to the manuiacture of photographic materials for color pho-' 'l silver without removal of coloring matter leaves tography having two or more light-sensitive emulsions on one or more supports.

In light-sensitive photographic materials, more especially those for .use in colour photograp y it is, as is known, often desirable to incorporate pigments, dyes, dye-derivatives or dye- -i'orming' substances in photographic silver salt emulsions having water-soluble or water-insoluble colloid binders or in non-sensitive layers having watersoluble colloid binders such as gelatine. I use the term dye body" herein to designate any pigment, dye, dye-derivative or dye-forming substance which it may be desired to incorporate in light-sensitive o'r'non-sensitive layers. I use the term non-sensitive herein to designate any layer not {adapted to give rise to image iormaion therein on exposure of the sensitive emulsion or emulsions associated therewith. I'use the term dye derivative" herein todesignate any derivative of a dye from which the dye can be formed in the emulsion or other colloid binder 25 e. g. by oxidation or reduction. Examples of v often required to contain sensitizing dyes to modify their spectral sensitivity or to contain other dye bodies for the production of colored images, e. g. in color photography. Such layers may consist of or contain silver salt emulsions such as gelatino-silver halide emulsions or' silver halide collodion emulsions with which it may be desired a to associate dye bodies. Such dye bodies may be used for the subsequent production pf coloured separation images by an imagewise bleach out process. F11 dye derivatives or dye-forming substances are used there may be treated for the imagewise production of dyestuffs or for the ,dif-

developing agent used for developing the exposed silver salt to metallic silver with the production of coloring matter in the region where the silver is developed. Subsequent removal of metallic a substantially clear. transparent dyeimage. In'makin'g photographic materials containing sensitive or non-sensitive colloid layers, it has been customary to incorporate dye bodies directly in the colloid medium where its-presence is, re-

quired, such colloidmedium being gelatine in most cases. Serious difllculties are often encountered in doing this particularly when the colloid medium is water soluble; Thus when the dye body has a low solubility in the colloid medium it may not be possible to incorporate the desired quantity or the dye body may separate out in large crystals or aggregates in the processoi coating and drying the colloid. Another trou ble frequently mat is the tendency of the dye body to difluse out or the layer or emulsion in which it is incorporated into an adjacent layer or layers or emulsion or emulsions. I use the term "adjacent" herein to designate a layer or emulsion not separated from the layer or emulsion containing the dye body by any water-impermeable layer such as the support although it may be separated by a water-soluble colloid such as gelatine. .This is the case when layers, one or 'moreoi' which contain dye bodies, are cast one upon another, with or without intermediate plain colloid layers or where emulsions are disposed in the iorm oi differentially sensitized grains in a single body of binder such as gelatine. British Patent specification No. 503,752 describes various arrangements of three differentially color sensitized emulsions on a single support wherein the dlmculty of wandering oi dye-bodies may be encountered. If some dye bodies wander from a 40 non-sensitive layer into a sensitive layer they may have a deleterious action suchas a fogging or desensitizing action. If they wander from one sensitive emulsion toanother and such emulsions are destined to record different color sensations, 1

the true color rendering may be detrimentally affected. Such wandering may take place during coating or drying or during processing.

Numerous proposals have been made to produce color couplers which will not wander or fus Production of'dyestufi for subsequent image-5 diiiuse from the emulsions in which they are wise bleaching. If dye-forming substances are used, these may be color couplersservin 1 the production of colored separation images by color development I use the term color coupler" incorporated. In some of these proposals attempts were made so to alter the color couplers that they would have an amnity tor gelatine; e. g. by the introduction of groups said to be "subherein to designate any body which iscapable of I stantive'.-' In other, groups oi high molecular combining with the oxidation products of the weight were introduced into the color couplers.

. photographic reproduction.

Although it has-been proposed to cause color couplers to be absorbed on to the silver halide grains with the object of avoiding difiusion, most of the methods proposed have involved chemical synthesis of a more complex color coupler from a simpler color coupler. When this is done there is usually an undesirable tendency for the absorption range to become wider and the absorption curve to become flatter, resulting in'less pure .dye images.

degree on the emulsion. If they are not adequately dispersed then the dye which is formed tends to be produced in localized spots lresulting in a granular appearance which impairs die The use. of an auxiliary carrier, such as a water-insoluble water-permeable cellulose derivative, natural resin or synthetic resin having the dye body dissolved or dispersed therein has been proposed as a means of preventing ormlnimising diffusion. It sometimes happens that when diflfusion 01" a color coupler or other dye body is retarded in this way, the further difficulty is sometimes encountered that the processing baths employed do not act to a sufficient extent or sufilcient rapidity upon the colour. coupler or other dye body. It occasionally happens,- for example, that when. an emulsion containing an insoluble coupling component or one assoc ated with a water-insoluble water-permeable binder has been exposed in the usual manner and developed with the customary type of color coupling developer, a very weak color or, even no color at all is produced.

It is also sometimes d flicultwhen a colour coupler or other'dye body is associated with a waterinsoluble water-permeable binder, to find a binder which has the necessary solvent action for the color coupler or other dye body wh ch is also sufllclently permeable to aoueous processing solut ons. If the water-insoluble water-permeable binder has insufllcient solvent act on for the dye body. there is a tendency for the dye body or the dye formed from it or both to separate as a crystalline deposit on ageing of the finished emulsions.

One object of my invention is a method of incorporat ng a dye body in a colloid medium in which it has only low solubility which method prevents or minimises the risk of the dye body separating in large crystals or aggregates.

Another object of my invention is to incorporate a dye body in a colloid medium so that diffusion therefrom is prevented or minimised Another object is to provide a water-insoluble, water-permeable binder having a good solvent action on dye bodies and with which dye bodies may be incorporated in colloid media.

The present invention in its broadest aspects comprises incorporating dye bodies in photographic colloid binders, for example in silver salt emulsions or light-screening layers, in the presence of hydrolysed natural resins or of resin esters or ethers or ether esters formed with organic or inorganic acids or alcohols. The hydrolysed natural resins can be used in the form of their salts, either water-solubleor water-insoluble, or their esters, ethers or ether esters. The invention does not, however, include the use of salts of hydrolysed lac.

I have found that by the use of hydrolyzed ,naturalresins or resin derivatives as described of the ethers.

above in conjunction with dye bodies, better results can often beobtained than by the use of the resins themselves or salts of resins themselves. Among the advantages secured by the use of hydrolysed natural resins or resin derivatives as described above are that, as a rule,

- 1. They form a finer dispersion than the parent resin.

2. They have an increased capacity for dissolving the dye body.

3. By adjusting the degree of hydrolysis in the case of hydrolysed resins, or by using suitable acids .or alcohols for esteriflcation or etherification in the case of resin derivatives, products of the same refractive index as gelatin can be obtained thus eliminating light scatter and matte surfaces when gelatine is employed as the carrier.

The hydrolysed resins are all oils'or plastic at normal room temperatures and have higher acid values than the parentresin.

'The principal difierence between hydrolysed resins and the resin derivatives referred to is that the former are completely soluble in or removed by alkaline solutions such as developers in a short time while the latter can be made completely insoluble in alkaline liquids such as developers if required by complete esterfication Whether the hydrolysed resins or the resin derivatives are employed in any particular case will be determined byv whether in.- solubility in alkali or solubility in' alkali isthe more favourable condition for the use to which the photographic material will be put.

The photographic materialof the present invention has one or more layers on one or more supports and at-least one layer has a colloid more-light-sensitive emulsions of silver salt col-- non-diffusibly incorporatedin colloid media so that processing baths may nevertheless act on rapidly.

loid binder on one or more supports and have at least one non-sensitive layer having a watersoluble binder, such as gelatlne, containing a dye body as herein defined and a hydrolyzed natural resin or asalt thereof oran ester or ether or ether-ester of a natural resin or of a hydrolysed natural resin. Alternatively, the

photographic material of the present invention may have one or more light-sensitive emulsions of silver salt in colloid binder on one or more supports at least one of the emulsions containing at least one dye body as herein defined and such as gelatine.

aseasco Acetic-acid lac esters a hydrolysed natural resin or a salt thereof or an ester or ether or ether-ester of a natural resin or of a hydrolysed natural resin Such dye body may comprise a color coupler or a sensitizing dye or both.

The colloid binder of the emulsion or emulsions containing thecolor coupler, sensitizing dye or other dye body may be a water-soluble colloid The material may be one in which two or. more emulsions are coated in superimposed layers on a single support, preferably all on one side of the support. There may be three difierentially color sensitized emulsions on the same side of the sup port, preferably in superimposed layers.

When a non-sensitized layer contains the dye body, this may serve as a light screening layer v e. g. an anti-halation layer on the back of a support which has a silver salt emulsion or silver salt emulsions on its front, or a light-filter layer arranged over a silver salt emulsion or emulsions or between two silver salt emulsions. I

Anti-halation layers, as is known, most desirably have a water-insoluble but alkali soluble binder so that they will strip ofi and dissolve in the usual alkaline developing baths. The method of the present invention for incorporating a dye body as herein defined in a photographic layer consists in dissolving or dispersing the dye body in a hydrolysed natural resin or a salt thereof or in an ester, ether or ether-ester of a natural resin and then mixing such solution or dispersion with the colloid binder or the'photographic layer. This method" is suitable for incorporating a color coupler or sensitizing dye or both in a silver salt emulsion.

Butyric acid-lac esters Lauric acid-lac esters See London Shel- Stearic acid-lac esters lac Research Bu- Rosin lac esters reau Technical Oleic acid lac esters Paper No. 15

.' Linseed oil lac esters- Phosphoric acid-lac esters Fatty a'cid--lac glycerol esters-see above No. 12 and No. 14.

Glycol ether-crotonic and cinnamic esters of lac--No. 1'7 and No. 19;

' Esters and ethers of the other resins can be prepared in a similar way. The ethers and esters of the hydrolysed resins are also formed in the same way.

As already stated, the hydrolysis of natural resins can"be carried out with causticsoda and bleaching can if desired be carried out simultaneously, e. g. with'sodium hypochlorite. The hydrolysis products generally have lower softening-melting ranges and higher acid values than the original resins. They tend, therefore, to be precipitated as oily particles onaddition to solu-.

tions of gelatine or other water-soluble binder (of which agar-agar is an example) and, as valready pointed out, are more'readi'ly attacked and dissolved by alkaline processing solutions. The hydrolysis products 'have an increased capacity for dissolving dye bodies, especially color couplers so that on precipitation in a water-soluble binder which may be' a photographic emulsion the dyebody does not tend so readily to crystallize out. Furthermore hydrolysis products of many resins, e. g. softJac, have refractive indices which are the same as that of gelatin so that even if the resin is not removed during processing as the sodium salt the free resin acid formed in ing light scatter; They are precipitated as resinous oils on pouring from thin water miscible solvents into gelatin or water-wetting a ent solutions. One can also add the dye body and resin separately but results obtained by this method are inferior to that already mentioned.

To get good resin dispersion the resin solutions should preferably be less than 10 per cent unless homogenization is undertaken after precipitation. The addition of a wetting agent to the resin solution, e. g. Lubrol W. improves the ease I of dispersion. If non-solubility in processing solutions is desirable' the alkali-solubility of the resin carrier can be reduced by forming esters or ethers or ether-esters with organic or inorganic acids or .al-.

cohols. Oily products are formed in many cases.

lf llylrolysed resins can also. be esterified or etheri- Thefollowing derivatives illustrate the compounds used: v i l-lfydrolysed lac Hydrolysed sandarach Hydrolysed soft lac Hydrolysed 'copals Hydrolysed hard lac Hydrolysed colophony.

Hydrolysed damar Vdrolysed mastic a r 1 the acid fixer is invisible where the layer dries.

, One important use of the invention is in antihalation layers particularly for roll film. Such roll film may have one or more emulsion layers on one side of the support and the anti-halation layer on the other. It is important that the dye present in the anti-halation layer shall not wan- ,der because (a) it should not stain the film support, and (b) when the film is rolled up the antihalation layer is in layer.

'Another important use of the invention is in filter layers present between different emulsion.

layers in amultilayer color photographic element such as the .double layer" and "triple layer elements described in British Patent specification No. 503,752. Such an element have successively coated on one side of a single support, a red sensitized emu sion, a green sensitized emulsion and a not-specially color-sensitized emulsion. Between this latter emulsion and the green sensitized emulsion there may be a yellow colored filter layer which can advantageously be made with the aid of the present invention. There may also be a yellow or red colored filter layer between the redsensitized emulsion and the green sensitized emulsion which can also be made with the aid of the present invention.

' A further important use of the invention is in a color-photographic material having three diiferentially color sensitized silver salt emulsions on a single support. As already stated the emulsions may be arranged in many ways as set forth in British Patent specification No. 503,752. One 'imm antexample of sucha material is that just described above having three superimposed emulcontact with the emulsion as an anti-halation layer. water-soluble dye, is so fixed that it is dimcult or may be used in practicing the invention, such as thosedescribed in British Patent specifications Nos-458,664, 458,665, 478,942, 478,983, 478,989, 478,990, 493,952, 496,196, 496,245, 519,695, 524,040,

538,914, 537,921, 537,696 and 541,589.

Dyes suitable for use in silver salt. emulsions include azo dyes capable of being bleached inthe region of a silver image and soluble in organic solvents such as n-butyl alcohol. Va-t'dyes such as anthraquinone dyes soluble in organic solvents may be used.

Dyes suitable for use in filter layers or anti- I halation layers are described in British Patent specification No. 540,365.

Example 1 0.1 gram Methyl Red, 0.1 gram Lubrol W and 1.0 gram hydrolysed colophony in cc. alcohol and 10 cc. acetone are added with stirring to 100 cc. of gelatin solution. The resulting mixture is coated as a filter layer, e. g. between ared-sensitized emulsion layer and a green-sensitized emulsion layer.

The colophony is hydrolysed by dissolving 25 emulsions and. 5 cc. toluene are poured into 100 cc. of a '7 per cent gelatin solution. This can be coated grams thereof in 200 cc. alcohol and boiling for hour with a solution of 8 grams of. caustic soda in 300 cc. water. It is precipitated with dilute acid, extracted with butyl alcohol, dried and the alcohol driven off by warming, if desired under reduced pressure.

Example 2 l 0.2 gram Magenta P. 120 (water-soluble) (sold by I. C. I. Dyestufls Ltd) 1 gram hydrolysed soft lac resin and 0.1 gram Lubrol W, in 20 cc. alcohol -are,poured into 100 cc. of a 7 per cent gelatin solution. The resulting mixture is coated for use The dye, although even impossible to remove it by washing with water. An alkaline photographic developer will,

alcohol and 5 cc. acetone are precipitated by stirring into 100 cc. of a 7 per cent gelatin solution. The resulting mixture can be coated to'form a filter layer. The preparation of the lac ester can be found on page 6 of the above mentioned Technical Paper No. 15.

Example 5 0.2 gram 2:4-dlhydroxyazobenzene and 2 grams ethylene glycol-lac-ester dissolved in 20 cc. spirit for use as a filter layer. The preparation of the lac-ether is described in the above-mentioned Technical Paper No. 17 p. 6.

Water-soluble salts, such asthe sodium salts or water-insoluble salts or alcohol-soluble salts or alcohol-insoluble salts of the'hydrolysed resin or resin esters or ethers can be used in a like manner.

' Example 6 0.2 gram 2:4-dihydroxyazobenzene and 2 grams of the sodium salt of hydrolysed colophony (see Example ,1) in 30 cc. industrial spirit (alcohol) are stirred into 150 cc. 7 per cent gelatin solution. A layer coated from this mixture contains the dye well dispersed and can be used as alight filter.

Example 7 0.2 gram Ink Blue and 2 gramsof the calcium salt (alcohol soluble) of hydrolysed hard lac are dissolved in 35 cc. spirit then stirred into 200 cc. 7 per cent gelatin solution. The Ink Blue is firmly fixed and the mixture can be coated for use as anti-halation layer.

Example 8 To 800 cc. of a contrasty bromide emulsion containing the equivalent of 20 grams silver nitrate is added a solution of .003 gram 5-[-2(2- ethyl-l-benzoxazolylidene) -ethylidene] -3 -ethyl- 1-phenyl-2-thiohydantoin British Patent specification No. 450,958 Example 43) in 10 cc. acetone. After 10 minutes, 20 cc. of a 1 per cent solution of hydrolysed hard lac resin (acid value 200) is added. This emulsion is then mixed at 30 C. with 800 cc. of a soft bromide emulsion containing the equivalent of 20 grams silver nitrate to' which has been added 20 cc. of a1 per cent solution of hydrolysed hard lac resin. The mixhowever dissolve the resin and bleach the dye. y

. The lac is hydrolysed by dissolving 25 grams soft lac (bleached and dewaxed) in. 50 cc. spirit and standing for 1 hour at 20 C. with 200 cc. of a 4% aqueous solution oi caustic soda.

v Example 3 I 0.2 gram Malachite Green, 1 gram. hydrolysed gum mastic and 0.1 gram Lubrol W, in 15 cc. ace

tone and 5 cc.- industrial spirit (alcohol) are stirred into 100 cc. of a 7 per cent gelatin solution. The solution can be coated for use as an anti-halation layer, the water-soluble dye being firmly fixed until the resin has been acted upon by alkali. Th hydrolysed mastic is prepared by dissolving 25 grams mastic in 200 cc. acetone and boiling for 1 hour with 200 cc. of a 5 percent aqueous solution of caustic soda.

Example 4 0.2 gram 2'- hydroxy-5-methoxy-azobenzene and I phony in 10 cc. alcohol.

1 gram butyric acid-lac ester in 10 cc. methyl 76 ture' is kept 60 minutes and coated on paper. -Wandering of the dye on processing the coating is very much less than in the case of an emulsion containing no hydrolysed resin but otherwise similar. I

' Example 9 To 800 cc. of a contrasty chloride emulsion containing the equivalent of 20 grams silver I nitrate is added a solution of 0.003 grams dye (as in Example 8) 0.03 gram hydrolysed colo- After 10 minutes 20 cc. of a. 1 per cent solution of a lac-acetic acid condensate is added. The emulsion is then mixed with 30 C. with 800 cc. of a soft chloride emulsion containing the equivalent of 20 grams silver nitrate to which has been added 20 cc. of a 1 per cent solution of'the same lac-acetic acid condensate.

' when the emulsion is coated as a layer, a

marked-decrease of dye wandering ls'noticeable" as compared with an emulsion not containing hydrolysed resin but otherwise similar; The

. 2,869,469 hydrolysed colophony is obtained by cooking a solution of 25 grams colophony in 300 cc. alcohol with 8 gram caustic soda dissolved in 50 cc. water for an hour then precipitating with acid.

E's-ample 10 2.5 g. P- nitrobenzylcyanide, 25 grams hydrolysed soft lac resin (see Example 2) and 0.5 gram Lubrol W are dissolved in a mixture of 250 cc. spirit and 250 cc. acetone and the whole stirred into 2,500 cc. of silver bromide emulsion containing 80 grams silver nitrate. A layer whichhas been coated and dried gives on exposure and development with'a developing solution containing p-diethylamino. aniline as the developing agent a brilliant magenta image which shows littleevidence of any dye wandering.

Example 11 5 gram o-phenylphenol (see specification No. 458,665) 25 grams hydrolysed colophony (see Example 1) and 0.5 gram N:N'-ethylene dloxy methyl pyridine perchlorate (dispersing agent) gram ethyleneglycol-lac ether are dissolved in 500 cc. industrial spirit (alcohol) and added to 2,500 cc. of a silver bromide emulsion containing 150 grams silver nitrate. The emulsion is coated on a support. 7

The emulsions of Examples 11 and 12 give well dispersed dye images (blue and magenta respectively) on exposure and colour development. The coupler does not noticeably wander into adjacent layers.

I declare that what I claim is: 1. A photographic material having on a supportat least one light-sensitive emulsion of silver salt containing color coupler and an auxiliary color coupler and hydrolysed soft lac resin.

4. A gelatino-silver halide emulsioncontaining color coupler and ,ethyleneglycol-lac ether.

EDWARD FBowEs KNo'rr, 

